nfs: Fix potential posix_acl refcnt leak in nfs3_set_acl

nfs3_set_acl keeps track of the acl it allocated locally to determine if an acl
needs to be released at the end.  This results in a memory leak when the
function allocates an acl as well as a default acl.  Fix by releasing acls
that differ from the acl originally passed into nfs3_set_acl.

Fixes: b7fa0554cf1b ("[PATCH] NFS: Add support for NFSv3 ACLs")
Reported-by: Xiyu Yang <xiyuyang19@fudan.edu.cn>
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

diff --git a/fs/nfs/nfs3acl.c b/fs/nfs/nfs3acl.c
index c5c3fc6e6c600b427c991d4be3a83879bbd2b48c..26c94b32d6f49e15f2c4e4a50d219f6a8592e034 100644 (file)
--- a/fs/nfs/nfs3acl.c
+++ b/fs/nfs/nfs3acl.c
@@ -253,37 +253,45 @@ int nfs3_proc_setacls(struct inode *inode, struct posix_acl *acl,
 
 int nfs3_set_acl(struct inode *inode, struct posix_acl *acl, int type)
 {
-       struct posix_acl *alloc = NULL, *dfacl = NULL;
+       struct posix_acl *orig = acl, *dfacl = NULL, *alloc;
        int status;
 
        if (S_ISDIR(inode->i_mode)) {
                switch(type) {
                case ACL_TYPE_ACCESS:
-                       alloc = dfacl = get_acl(inode, ACL_TYPE_DEFAULT);
+                       alloc = get_acl(inode, ACL_TYPE_DEFAULT);
                        if (IS_ERR(alloc))
                                goto fail;
+                       dfacl = alloc;
                        break;
 
                case ACL_TYPE_DEFAULT:
-                       dfacl = acl;
-                       alloc = acl = get_acl(inode, ACL_TYPE_ACCESS);
+                       alloc = get_acl(inode, ACL_TYPE_ACCESS);
                        if (IS_ERR(alloc))
                                goto fail;
+                       dfacl = acl;
+                       acl = alloc;
                        break;
                }
        }
 
        if (acl == NULL) {
-               alloc = acl = posix_acl_from_mode(inode->i_mode, GFP_KERNEL);
+               alloc = posix_acl_from_mode(inode->i_mode, GFP_KERNEL);
                if (IS_ERR(alloc))
                        goto fail;
+               acl = alloc;
        }
        status = __nfs3_proc_setacls(inode, acl, dfacl);
-       posix_acl_release(alloc);
+out:
+       if (acl != orig)
+               posix_acl_release(acl);
+       if (dfacl != orig)
+               posix_acl_release(dfacl);
        return status;
 
 fail:
-       return PTR_ERR(alloc);
+       status = PTR_ERR(alloc);
+       goto out;
 }
 
 const struct xattr_handler *nfs3_xattr_handlers[] = {